Alignment device

ABSTRACT

An alignment device provides one or more references, such as laser lines and planes in horizontal and vertical orientations. One version of the alignment device includes an optics mounting assembly situated in a pivot socket on a frame to provide an output beam. A spring system and one or more alignment assemblies align and secure the optics mounting assembly in the socket. As a result, the output beam has a desired orientation with respect to true level. The spring system holds the optics mounting assembly in communication with the alignment assemblies to reduce system backlash. One implementation of the pivot socket has a surface in the form of a sphere&#39;s interior surface. A set of support members on the optics mounting assembly rest on the pivot socket&#39;s spherical surface—causing the output reference beam to extend from the center of a sphere including the socket&#39;s spherical surface. This reduces the translation of the output reference beam&#39;s origin when the optics mounting assembly pivots in the socket.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This Application is related to the following applications:

[0002] U.S. patent application Ser. No. 09/928,244, entitled “LaserAlignment Device Providing Multiple References,” filed on Aug. 10, 2001and

[0003] U.S. patent application Ser. No. 10/004,694, entitled“Servo-Controlled Automatic Level and Plumb Tool,” filed on Dec. 4,2001.

[0004] This Application incorporates each of the above-identifiedapplications herein by reference.

CLAIM OF PRIORITY

[0005] This application claims the benefit under 35 U.S.C. §120 of, andis a continuation-in-part of, U.S. patent application Ser. No.10/004,694, entitled “Servo-Controlled Automatic Level and Plumb Tool,”filed on Dec. 4, 2001, which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

[0006] 1. Field of the Invention

[0007] The present invention is directed to the field of alignmentdevices.

[0008] 2. Description of the Related Art

[0009] People undertaking construction and repair projects frequentlyrequire the use of reference guides. People employ reference guides onprojects ranging from professional construction of large city buildingsto amateur home improvement. For example, a person installing a borderon the walls of a room requires a level reference line on each wallidentifying a placement position for the border.

[0010] Traditional alignment tools for assisting in the manual placementof reference guides include straight edges, rulers, protractors,squares, levels, and plumb bobs. More recently, tool manufacturers haveintroduced laser alignment devices that provide references, such aspoints, lines, and planes. These laser alignment tools include, simplepointers, pointers with bubble vials, self-leveling pointers, multiplebeam pointers, and devices producing a sheet of light.

[0011] In many instances a project requires the use of multiplereferences. For example, a project may require the use of both referencelines and planes in horizontal and vertical orientation. In manyinstances this requires the use of multiple alignment tools—forcing aperson to have all of these tools available for the project. Thepurchase, maintenance, storage, and transportation of several alignmenttools are undesirable inconveniences that consume time and money. Insome circumstances it is simply impractical to have multiple alignmenttools readily available on a job site.

[0012] It is desirable for a single alignment tool to provide multipletypes of references in both horizontal and vertical orientations. Thisreduces the number of tools required for a job—allowing users theconvenience of purchasing, maintaining, storing, and transporting areduced number of tools. The user's convenience in using a multiplereference tool, however, must not be outweighed by the expense of thetool. The multiple reference alignment tool also needs to meet theuser's accuracy expectations.

[0013] In electromechanical control systems, such as an automatedreference tool, backlash can be a leading source of inaccuracy. In acontrol system, the movement of a first object directs the motion of asecond object. Backlash is the phenomenon of mechanical hysteresis thatoccurs when the direction of motion of the first object is altered.Mechanisms controlling the motion of the second object by directing themotion of the first object need to account for backlash. Otherwise, thecontrol system's accuracy will be compromised. A multiple referencealignment tool needs to either reduce or compensate for backlash in allof the orientations the tool will be used.

[0014] Traditional systems frequently employ expensive high precisioncomponents to overcome the problem of backlash and minimize othersources of inaccuracy. However, this can result in increasing theexpense of a reference tool beyond the acceptable threshold of manyusers. It is desirable to reduce backlash effects and other inaccuracieswithout necessitating the use of expensive components.

SUMMARY OF THE INVENTION

[0015] The present invention, roughly described, pertains to analignment device capable of providing multiple references in differentorientations—reducing the number of alignment devices a user needs for ajob site. One implementation of the alignment device provides ahorizontal set of laser references and a vertical set of laserreferences. For each set of references, users have the ability to selecta plane, line, or pointing reference. In one version of the alignmentdevice, users can also rotate the position of the vertical andhorizontal reference points and lines. In a further embodiment, userscan adjust the positions of the laser planes on incident surfaces.

[0016] One embodiment of the alignment device includes an opticsmounting assembly mounted in a pivot socket on a frame. A spring systemand one or more alignment assemblies secure the optics mounting assemblyin the pivot socket. The optics mounting assembly includes a lightsource supplying a light beam. In one embodiment, the light source is alaser emitting diode supplying a laser beam. The source beam is incidenton a reflector that produces an output reference beam. At rest, thereflector produces a reference point. A motor mounted on the opticsmounting assembly spins the reflector to generate a reference plane. Themotor dithers the reflector to generate a reference line. In a furtherembodiment, a user can manually position the output reference beam.

[0017] One implementation of the pivot socket has a surface in the formof a sphere's interior surface. The optics mounting assembly extendsthrough the pivot socket and includes a set of support members that reston the pivot socket's spherical surface. The support members hold thereflector in a position that results in the output reference beamoriginating at the center of a sphere that includes the pivot socket'sspherical surface. This minimizes translation of the output referencebeam's origin when the optics mounting assembly pivots in the socket.

[0018] The spring system includes a set of one or more springs exertingforce on the optics mounting assembly. The spring force pulls the opticsmounting assembly support arms against the spherical surface of thepivot socket. The spring force also attempts to rotate the opticsmounting assembly about a pivot point at the center of a sphere thatincludes the spherical surface of the socket. The optics mountingassembly includes a set of extension arms that communicate with thealignment assemblies. The alignment assemblies apply forces on theextension arms that oppose the rotation induced by the springforce—holding the optics mounting assembly in a desired position withinthe pivot socket.

[0019] Alignment assembly movements direct the movement of the opticsmounting assembly—altering the position of the output reference beam. Inone embodiment, the alignment device includes a level sensor thatsupplies signals indicating whether the optics mounting assembly isnormal to true level. A control subsystem in the alignment deviceemploys these signals to drive the alignment assemblies. The alignmentassemblies provide forces to the optical mounting assembly extensionarms—positioning the optics mounting assembly normal to true level. Thisresults in an output reference beam parallel to true level.

[0020] The spring system assists in removing backlash from the alignmentdevice's controlled movement of the optics mounting assembly. The springsystem holds the extension arms flush against pads on the alignmentassemblies. The optics mounting assembly support arms are held flushagainst the spherical surface of the pivot socket by the combined forcesof the (1) alignment assemblies on the extension arms and (2) the springsystem on the optics mounting assembly.

[0021] In one implementation, each alignment assembly pad is mounted ona lead screw with a gear driven by a motor controlled pinion. Thepinion's teeth are tightly coupled to the gear's teeth to further reducebacklash. The pinion and gear are drawn together by a spring force thatallows the gear and pinion teeth to separate, as needed, to minimizebacklash and compensate for run-out.

[0022] The alignment device also produces an accurate reference beamwhen the device is rotated by ninety degrees—converting a horizontallaser plane generated by the reference beam into a vertical laser plane.The spring system and alignment assemblies provide the same forces inthe rotated orientation to secure the position of the optics mountingassembly and remove backlash effects. In such an implementation, thealignment assemblies can be employed to control the positioning of theoutput reference beam on an incident surface. For example, the alignmentassemblies may horizontally translate a vertical laser plane output onthe incident surface.

[0023] Further implementations of the alignment device includeadditional features for enhancing accuracy. For example, the reflectorcan be a penta-prism mounted with a predefined pitch for reducing theeffects of satellite output beams. The penta-prism may also include apredetermined pitch deviation. The penta-prism is then mounted within aknown roll range to achieve a more accurately positioned reference beam.

[0024] Alignment devices in alternate embodiments of the presentinvention may provide less than all of the references described above.One version of an alignment device according to the present inventiononly provides a single type of reference in a single orientation.

[0025] Aspects of the present invention can be accomplished usinghardware, software, or a combination of both hardware and software. Thesoftware used for the present invention is stored on one or moreprocessor readable storage media including hard disk drives, CD-ROMs,DVDs, optical disks, floppy disks, tape drives, RAM, ROM or othersuitable storage devices. In alternative embodiments, some or all of thesoftware can be replaced by dedicated hardware including customintegrated circuits, gate arrays, FPGAs, PLDs, and special purposecomputers.

[0026] These and other objects and advantages of the present inventionwill appear more clearly from the following description in which thepreferred embodiment of the invention has been set forth in conjunctionwith the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0027]FIG. 1 depicts the exterior of an alignment device in oneembodiment of the present invention.

[0028] FIGS. 2A-2B show perspective views of internal components in oneversion of the alignment device in FIG. 1.

[0029]FIG. 2C shows a front view of internal components in one versionof the alignment device in FIG. 1.

[0030]FIG. 2D shows a rear view of internal components in one version ofthe alignment device in FIG. 1.

[0031]FIG. 2E shows a perspective bottom view of internal components inone version of the alignment device in FIG. 1.

[0032]FIG. 2F shows a bottom view of internal components in one versionof the alignment device in FIG. 1.

[0033]FIG. 2G shows a top view of internal components in one version ofthe alignment device in FIG. 1.

[0034]FIG. 2H shows a side view of internal components in one version ofthe alignment device in FIG. 1.

[0035]FIG. 2I shows a cross-sectional side view of internal componentsin one version of the alignment device in FIG. 1.

[0036]FIG. 3 is a side-section view of one implementation of a dual axislevel sensor.

[0037]FIG. 4 is a perspective view of an implementation of a dual axislevel sensor.

[0038]FIG. 5 depicts an embodiment of a quadrature detector inaccordance with the present invention.

[0039]FIGS. 6 and 7 are side-section views of additional level sensorembodiments in accordance with the principles of the present invention.

[0040]FIG. 8 shows a cross-sectional view of a jack screw assemblymounting a laser sensor to an optics mounting assembly in one embodimentof the present invention.

[0041]FIG. 9 shows a penta-prism used in one embodiment of the presentinvention as a reflector.

[0042] FIGS. 10A-10C shows alternate embodiments of a penta-prism andimplementations for mounting a penta-prism.

[0043] FIGS. 11A-11B show various perspective views of one embodiment ofa rotation cap for use in the alignment device shown in FIG. 1.

[0044]FIG. 12 shows a perspective view of the spring mechanism in therotation cap shown in FIGS. 11A-11B.

[0045]FIG. 13 is a block diagram for one implementation of a controlsubsystem for the alignment device in FIG. 1.

[0046]FIG. 14 is a flowchart describing one implementation of a processfor leveling a horizontal reference.

[0047]FIG. 15 is a flowchart describing one implementation of a processfor setting a horizontal reference to a predetermined offset.

[0048]FIG. 16 is a flowchart describing one implementation of a processfor leveling a vertical reference.

[0049]FIG. 17 is a flowchart describing one implementation of a processfor setting a vertical reference to a predetermined offset.

[0050]FIG. 18 is a flowchart describing one version of a process forpositioning horizontal and vertical references.

DETAILED DESCRIPTION

[0051] I. External Operation

[0052]FIG. 1 shows a laser alignment device 1 in accordance with thepresent invention. Output beam 8 emanates from beam turret 4, which ismounted on top of alignment device 1. In one embodiment, output beam 8is a laser beam, while in alternate embodiments output beam 8 can be anytype of light, including visible and invisible light. Alignment device 1uses output beam 8 to provide reference points, lines, and planes onincident surfaces. In the orientation shown in FIG. 1, alignment device1 provides horizontal reference lines and planes. When alignment device1 is rotated by ninety degrees, output beam 8 provides verticalreference lines and planes. The rotated operation of alignment device 1is described below in greater detail.

[0053] The position of output beam 8 can be rotated to adjust theposition of a reference line or point. In one embodiment, a usermanually rotates rotation cap 6 on turret 4 to make an angularadjustment to the position of a output beam 8. In an alternateembodiment, alignment device 1 automates the angular adjustment ofoutput beam 8.

[0054] Local interface 10 on alignment device 1 includes control buttonsthat enable users to control the operation of alignment device 1. Thisallows users to generate and position horizontal and verticalreferences. In an alternate implementation, alignment device 1 includesa remote control receiver (not shown). The remote control receiverenables communication with a remote control, so a user can remotelydirect the operation of alignment device 1. One skilled in the art willrecognize that such a remote control receiver can support any one of anumber of different communication mediums and protocols. For example, inone embodiment, the remote control receiver supports radio frequencycommunication, while in another embodiment the receiver supportsinfrared signaling.

[0055] II. Internal Component Operation

[0056] A. Optics Alignment

[0057] FIGS. 2A-2I show one implementation of internal components foralignment device 1 in accordance with the present invention. FIGS. 2A-2Ishow different views as described above.

[0058] As shown in FIG. 2I, laser source 116 is mounted in mountingdevice 117, which is press fit into the hollow main shaft of opticsmounting assembly 24. In one embodiment, laser source 116 is a laseremitting diode coupled to circuit board 120, and mounting device 117 isa mounting joint, as described in U.S. patent application Ser. No.09/928,244. Collimating lens 134 is mounted in mount fixture 102, whichis fitted into the main shaft of optics mounting assembly 24 in linewith laser source 116.

[0059] Optics mounting assembly 24 houses hollow rotation shaft 98,which extends through guide rings 130 and 132. Within optics mountingassembly 24, rotating support ring 106 supports rotation shaft 98 inline with collimating lens 134. Shaft 98 supports reflector 96 in linewith lens 134 and laser source 116. A laser beam from source 116 extendsthrough lens 134 and onto reflector 96, which converts the beam fromsource 116 into output beam 8.

[0060] Motor 108 on optics mounting assembly 24 drives the rotation ofsupport ring 106 to rotate shaft 98. Shaft 112 from motor 108 is coupledto belt drive gear 114. Belt 104 extends around support ring 106 andgear 114. In operation, motor 108 rotates shaft 112, which rotates gear114. The rotation of gear 114 drives belt 104 to rotate support ring106—resulting in the rotation of output beam 8. As will be described inmore detail below, a control subsystem in alignment device 1 employsmotor 108 to perform the following operations: 1) spinning reflector 96to generate a laser plane reference; 2) dithering reflector 96 togenerate a partial laser plane reference; and 3) adjusting the rotationof reflector 96 to position a laser reference point. Encoder 110 ismounted on shaft 112 to facilitate dithering and pointing.

[0061] Alignment device 1 sets and secures the position of opticsmounting assembly 24, so that output beam 8 has a desired orientationwith respect to true level. In one embodiment, alignment device 1provides for optics mounting assembly 24 to produce output beam 8 asparallel to true level. In further embodiments, alignment device 1stabilizes optics mounting assembly 24 to have a predetermined offsetfrom true level.

[0062] Looking at FIGS. 2A and 2B, optics mounting assembly 24 extendsthrough pivot socket 22 on frame 20. Optics mounting assembly 24includes support members 28, 30, and 32 resting on section 23 of pivotsocket 22. Section 23 is formed in the shape of a section from aninterior surface of a sphere. Spherical section 23 extends downward fromrim 26 on socket 22, which is used to mount socket 22 to frame 20. In analternate embodiment, pivot socket 22 is formed in housing 20. Alignmentdevice 1 adjusts the position of optics mounting assembly 24 withinpivot socket 22 to give output beam 8 a desired orientation, such asparallel to true level.

[0063] In one implementation, members 28, 30, and 32 support opticsmounting assembly 24, so that output beam 8 originates from reflector 96at a point in the center of a sphere including spherical section 23.This center point also serves as the pivot point for assembly 24. Thiseliminates translation of the output beam origin when alignment device 1adjusts the position of optics mounting assembly 24 within pivot socket24. In alternate embodiments, the origin of output beam 8 may deviatefrom the sphere center point. In further embodiments, section 23 canhave a non-spherical surface.

[0064] Optics mounting assembly 24 includes extension arms 34 and 36. Aswill be described below, forces applied to extension arms 34 and 36assist in adjusting the orientation of optics mounting assembly 24. Inone implementation, extension arms 34 and 36 extend from the center ofoptics mounting assembly 24 perpendicular to each other.

[0065] Alignment assemblies within alignment device 1 provide adjustmentforces to extension arms 34 and 36. An alignment assembly incommunication with extension arm 36 includes motor 54, which rotatesshaft 52. Pinion 50 is mounted on shaft 52 and has teeth incommunication with teeth on gear 48. Lead screw 46 is mounted to gear48, so that screw 46 rotates when gear 48 rotates. Lead screw 46 extendsthrough lead nut 44, so that lead nut 44 translates along lead screw 46,based on the direction that screw 46 rotates. Alignment force pad 42 iscoupled to nut 44, so that pad 42 follows the translation path of nut44. In one embodiment, pad 42 includes interface contact 141 tocommunicate with extension arm 36. (See FIG. 2C.) In one suchembodiment, contact 141 has a spherical surface that enhances theability of pad 42 to move extension arm 36 without binding.

[0066] In one implementation, the teeth of pinion 50 are tightlyinterlocked with the teeth of gear 48 to reduce backlash in theoperation of the alignment assembly. As seen in FIG. 2H, gear 48 andpinion 50 are held in communication by spring 150—reducing backlash andcompensating for run-out. Spring 50 reduces backlash by pulling theteeth of gear 48 and pinion 50 tightly together in operation. Spring 50also reduces run-out. In this implementation, motor mount 152 supportsmotor 54. Motor mount 152 is mounted to frame 20 so that mount 152 canpivot pinion 50 away from and toward gear 48. Spring 150 is coupled tomotor mount 152 and frame 20 to facilitate the above-described operationbetween the teeth of gear 48 and pinion 50.

[0067] An alignment assembly in communication with extension arm 34includes motor 74, which rotates shaft 72. Pinion 70 is mounted on shaft72 and has teeth in communication with teeth on gear 68. Lead screw 66is mounted to gear 68, so that screw 66 rotates when gear 68 rotates.Lead screw 66 extends through lead nut 64, so that lead nut 64translates along lead screw 66, based on the direction that screw 66rotates. Alignment force pad 62 is coupled to nut 64, so that pad 62follows the translation path of nut 64. In one embodiment, pad 62includes interface contact 140 to communicate with extension arm 34. Inone such embodiment, contact 140 has a spherical surface that enhancesthe ability of pad 62 to move extension arm 34 without binding.

[0068] In one implementation, the teeth of pinion 70 are tightlyinterlocked with the teeth of gear 68 to reduce backlash in theoperation of the alignment assembly. Gear 68 and pinion 70 are held incommunication by spring 160 (not shown, but operating like spring 150)to reduce backlash and compensate for run-out. Spring 160 reducesbacklash by pulling the teeth of gear 68 and pinion 70 tightly togetherin operation. Spring 160 also reduces run-out effects. In thisimplementation, motor mount 162 supports motor 74. Motor mount 162 ismounted to frame 20 so that mount 162 can pivot pinion 70 away from andtoward gear 68. Spring 160 is coupled to motor mount 162 and frame 20 tofacilitate the above-described operation between the teeth of gear 68and pinion 70.

[0069] A spring set in alignment device 1 pulls optics mounting assembly24 into pivot socket 22 and directs extension arms 34 and 36 againstpads 62 and 42, respectively. In one embodiment, the spring set includestwo springs. In alternate embodiments, more or less than two springs areemployed.

[0070] As seen in FIGS. 2A-2C, the spring set has springs 38 and 40.Springs 38 and 40 each have a first end mounted to frame 20 and a secondend mounted to optics mounting assembly 24. Springs 38 and 40 eachsupply a force with a component pulling support member 28, 30, and 32against spherical section 23 of pivot socket 22. The forces from springs38 and 40 also have components that direct optics mounting assembly 24to rotate about a pivot point at the center of a sphere includingspherical section 23—pulling extension arms 34 and 36 against pads 62and 42, respectively. The forces from pads 62 and 42 on extension arms34 and 36, respectively, oppose the spring forces to hold opticsmounting assembly 24 in place.

[0071] The combined forces from springs 38 and 40 and alignment assemblypads 62 and 42 further reduce backlash in alignment device 1. Theseforces ensure that support member 28, 30, and 32 are flush againstspherical section 23 and extension arms 34 and 36 are flush against pads62 and 42, respectively. In operation, a control subsystem in alignmentdevice 1 adjusts the position of output beam 8 by using the alignmentassemblies to adjust the position of optics mounting assembly 24. Thelag time between driving motors 54 and 74 and effecting motion onextension arms 40 and 38 is minimized, because pads 62 and 42 are inconstant contact with arms 34 and 36, respectively.

[0072] Ideally, springs 38 and 40 are constant force springs that exertconstant forces regardless of how far they are stretched. In analternate embodiment, the spring force of springs 38 and 40 vary withthe distance the springs are stretched. In one such embodiment, springs38 and 40 are positioned to minimize the amount of stretching thesprings will experience. In one example, springs 38 and 40 are mountedto have the least amount of stretching possible and still applysufficient force to bias extension arms 36 and 34 onto pads 62 and 42and retain assembly 24 in socket 22. In one implementation, theseconstraints are met for the entire allowed range of motion for assembly24, including the rotated position of alignment device 1 to produce avertical reference plane as described herein. In an additionalimplementation, springs 38 and 40 do not contact assembly 24, except inthe points where springs 38 and 40 are anchored to assembly 24.

[0073] In a further implementation, extension arms 34 and 36 arereplaced by a pair of fine leads that rest on the grooves in lead screws46 and 66. Like arms 34 and 36, the fine leads are perpendicular to eachother. Rotating screws 46 and 66 causes the fine leads to slide up ordown screws 46 and 66, based on the direction of rotation causing theposition of optics mounting assembly 24 in pivot socket 22 to beadjusted. The fine lead embodiment also reduces backlash effects, sincethe leads rest directly on the grooves in screws 46 and 66. In oneembodiment, the fine leads are cylindrical and rigid with the dimensionsof standard piano wire. In one example, the fine lead diameter is 1millimeter or less.

[0074] Using the fine leads enables lead screws 44 and 46 to be drivendirectly by a motor, without the need for a gear and pinion mechanism.Screws 44 and 46 can be machined with very fine threads to allow foralignment adjustments with fine granularity. The fine screw threads donot create a need for expensive fine thread nuts, since lead nuts 44 and64 and pads 42 and 62 are no longer needed.

[0075] In another embodiment, a surface on either arm 34 or arm 36 thatcontacts pad 62 or pad 42 has a groove (not shown). The groove receivesthe respective spherical contact 140 or 141. The groove eliminatesrotation of the contact (140 or 141) on the arm (34 or 36). This ensuresthat arms 34 and 36 move along the desired path in response to alignmentassembly forces.

[0076] In yet another embodiment of the present invention, opticsmounting assembly 24 is replaced by a pendulum assembly that supportsthe above-described optical elements, including a motor for rotatingreflector 96. In one such embodiment, the pendulum base includes shaftsthat support one or more balancing weights. The alignment assemblies aremodified to slide the weights along the pendulum base shafts to adjustthe pendulum's center of gravity. These adjustments modify the positionof output beam 8.

[0077] B. Level Sensor

[0078] One version of alignment device 1 also has the capability toself-level—automatically bringing output beam 8 into a parallelrelationship with true level. As shown in FIGS. 2A-2I, level sensor 80is mounted to optics mounting assembly 24 to determine whether thecentral axis of assembly 24 is normal to true level. Level sensor 80provides level indicators to a control subsystem in alignment device 1.In response to the level indicators, the control subsystem drives motors54 and 74 to bring optics mounting assembly 24 into a perpendicularrelationship with true level. Example embodiments of level sensor 80 aredisclosed in U.S. patent application Ser. No. 10/004,694.

[0079] FIGS. 3-7 show various implementation of level sensor 80. FIG. 3shows detector element 230 in level sensor 80, including positionsensitive photo sensor 231, two-axis bubble level 232, aperturestructure 229, and detector light source 233 for generating detectorlight beam 234 (also referred to as detector light). Detector light 234is passed through bubble level 232 onto position sensitive photo sensor231, which detects whether bubble level 232 is leveled. Since theillustrated embodiment is tiltable in two degrees of freedom, a detector(e.g. bubble level) that is sensitive to tilting in two degrees offreedom is particularly appropriate. In other embodiments, an angledpair of one-dimensional tilt detectors may be used. It is to be notedthat other embodiments of detector elements can be used in accordancewith the principles of the present invention.

[0080] When bubble 235 is centered in level 232, the output beams arelevel. As bubble level 232 is tilted, bubble 235 moves from a centeredposition. This alters the position and amount of light 238 beingdetected by position sensitive photo sensor 231. In order to morequickly center bubble 235, bubble level 232 can include a curved bubbleface 236. In one embodiment, curved bubble face 236 has a radius ofcurvature of 70 millimeters. Position sensitive photo sensor 231 canincorporate any of a number of commercially available position sensitivedetectors sensitive to detector light 234. Examples include, but are notlimited to, quadrature detectors, charged coupled device (CCD)detectors, complementary metal oxide semiconductor (CMOS) image sensors(such as that taught in U.S. Pat. No. 5,461,425 to Fowler, et al. herebyincorporated by reference).

[0081]FIG. 4 is a perspective view of an embodiment of a two-axisdetector element 230 in accordance with the principles of the presentinvention. Light source 233 generates a beam that passes throughaperture 229 (See FIG. 3) to produce detector light beam 234 that isdirected through two-axis bubble level 232 onto quadrature detector 231.Detector light 234 passes readily through fluid 237 but is refracted inlarge part by bubble 235 of two-axis bubble level 232. Consequently,detector light 234 forms ring of light 238 surrounding dark spot 239.Ring 238 and spot 239 track the movement of bubble 235 as detectorelement 230 (and by consequence the output beams) is tilted. When darkspot 239 is centered in the middle of quadrature detector 231, outputbeam 8 is level. Therefore, when dark spot 239 is not centered onquadrature detector 231, adjustments are made to the alignment of opticsmounting assembly 24 until dark spot 239 is centered. In alternateembodiments, bubble 235 is replaced by another object to cast ring 238and spot 239. When bubble 235 is replaced by an object with a differentshape, the shapes of ring 238 and spot 239 change accordingly.

[0082] Adjustments are accomplished by selective activation of thealignment assemblies, until dark spot 239 is centered. This isaccomplished via a control subsystem in device 1 that adjusts theposition of optical mounting assembly 24 in response to informationreceived from quadrature detector 231. Bubble detector embodiments canbe constructed such that the inside walls of the bubble container arenot easily wetted by the fluids contained therein. In one example, thefluid can be water and the inside surface of the bubble container can betreated with hydrophobic material.

[0083]FIG. 5 depicts an embodiment of quadrature detector 231 featuringdark spot 239 and light ring 238. Such an embodiment is suitable for usein accordance with the principles of the present invention. As can beseen, quadrature detector 231 is fully illuminated within ring 238except for dark spot 239. As the sensor is tilted, dark spot 239 moveswith respect to quadrature detector 231. By tracking the motion of darkspot 239, quadrature detector 231 provides leveling information. Thedetector element is calibrated so that the output beams are leveled whendark spot 239 is centered in quadrature detector 231.

[0084] Quadrature detector 231 has four photodetectors 241, 242, 243,and 244. When light ring 238 impinges on the photodetectors of thequadrature detector, electrical current is produced. The magnitude ofthe current bears a relationship to the intensity of the light impingingon photodetectors 241, 242, 243, and 244. This light intensity isreduced by the presence of dark spot 239. The control subsystem indevice 1 measures the current produced by the photodetectors andprocesses the current to determine the location of dark spot 239 onquadrature detector 231. Typically, the current produced by thephotodetectors is conducted away from the detector using conductivelines 240, which can be connected to the control subsystem of device 1.The current from photodetectors 241, 242, 243, and 244 is processed todetermine the position of dark spot 139. One example of a method used todetermine spot 239 position is as follows: In order to determine theleft/right (L/R) position of the spot 239, current I241 produced fromphotodetector 241 is summed with current I243 produced by photodetector243, and current I242 produced by photodetector 242 is summed withcurrent I244 produced photodetector 244. The two sums are normalized andsubtracted from each other as shown in the equation below.

[(I241+I243)−(I242+I244)]/(I241+I243+I242+I244)=L/R Position Current

[0085] If the L/R position current is negative, it is known that spot239 is too far to the left. And, conversely, if the L/R position currentprovides a positive value, it is known that spot 239 is too far to theright.

[0086] The up and down positions of the spot can also be determined withquadrature detector 231. For example, in accordance with the followingequation:

[(I241+I242)−(I243+I244)]/(I241+I243+I242+I244)=Up/Down Position Current

[0087] If the up/down position current is positive, spot 239 is too low.Conversely, if the up/down position current is negative, then spot 239is too high. If the depicted spot 239 is used as an example, theleft/right position current will be negative and the up/down positioncurrent will be positive, which will allow the control subsystem todetect the fact that the beam is in the quadrant detected byphotodetector 243. Based on this information, the alignment assembliesare activated to adjust the position of optics mounting assembly 24 inorder to move dark spot 239 higher and to the right to level the bubble,thereby leveling output beam 8.

[0088] In another embodiment, light ring 238 (and dark spot 239) can begenerated by a plurality of laser emitting diodes (LED's). Once thedevice is leveled, the brightness of each of these LED's can be adjusteduntil dark spot 239 is centered on light detector 231. This isadvantageous because it can be accomplished electronically without theneed for costly and time consuming alignment steps. Instead, simpleadjustment of LED brightness can be used to center the dark spot 139 ina calibration step. One such embodiment can use four LED's.

[0089]FIG. 6 depicts the operation of yet another sensor embodiment 250.The sensor element is depicted in a cross-section view. Sensor element250 includes position sensitive photo sensor 281, bubble level device252, aperture structure 279, and detector light source 283 forgenerating detector light beam 284 (also referred to as detector light).As with the previously discussed embodiments, many different types ofdetector light sources 283 can be used, such as LED's. Detector light284 is passed through bubble level device 252 onto position sensitivephoto sensor 281, which detects whether bubble level device 252 isleveled (as is the case in FIG. 6). In the depicted embodiment, bubblefluid 253 is treated so that it is relatively opaque to detector light284. For example, a dye can be added to bubble fluid 253, so that aportion of the detector light passes through bubble level device 252 inthe region of bubble 255, but not through fluid 253. In other words,detector beam 284 passes readily through bubble 255 of bubble level 252,but is absorbed by fluid 253. As a result, detector light beam 256 exitsbubble level 252. Unlike the forgoing embodiments, where the detectorbeam is ring-shaped, this detector light beam 256 is characterized by alight spot defined by bubble 255. As with the previous embodiments,sensor 250 can be oriented so that beam 284 points downward.

[0090]FIG. 7 shows detector 250 tilted to the left. Consequently, bubble255 moves to the right, altering the amount and position of light 256sensed by position sensitive photo sensor 281. In accordance with theprinciples of the present invention, position sensitive photo sensor 281provides information to control circuitry (not shown here) whichactivates the alignment assemblies to correct the tilt in output beam 8.

[0091] The position sensitive photo detectors work similarly to thosedescribed hereinabove. The chief difference being that the electricalinformation is processed by the photo detectors in a slightly differentmanner to track the light spot as it moves across the photo detectors.Such methods are known to those having ordinary skill in the art. In afurther embodiment, invisible light can be employed in level sensor 80.

[0092] Another suitable detector element embodiment can use a pair ofsingle-axis bubble levels arranged at right angles to each other so thata level with respect to a first and second axis can be detected. Eachsingle-axis bubble level is associated with a corresponding light sourceand a corresponding position sensitive detector. Each correspondinglight source and corresponding position sensitive detector is arrangedto detect whether each single-axis bubble level is leveled. By levelingeach single-axis bubble level, the output beams can be leveled withrespect to the aforementioned first and second axes.

[0093] C. Level Sensor Mounting

[0094] As shown in FIG. 2C, screw assemblies 82, 84, and 86 mount levelsensor 80 to optics mounting assembly 24. FIG. 8 shows a cross-sectionalview of one embodiment of screw assembly 84, which can also be used forscrew assemblies 82 and 86. The screw assembly in FIG. 8 focusesstresses in the screw connection to reduce stresses on member 300extending from optics mounting assembly 24 and member 302 extending fromlevel sensor 80. Taking stress off of member 300 is particularlybeneficial, so that the chance of destabilizing optics mounting assembly24 is reduced.

[0095] Jack screw 312 has a threaded segment that extends into threadedchannel 320 in member 300. Screw 306 extends through Bellville washer308, washer 310, unthreaded channel 322 in jack screw 312, and threadedchannel 324 in member 302. Jack screw 312 rests on member 302, so thatchannel 322 in jack screw 312 is in line with channel 324 in member 302.Rotating jack screw 312 either pulls members 300 and 302 together ordrives members 300 and 302 apart along the central axis of channel 322in jack screw 312. Rotating screw 306 either pulls members 300 and 302together or drives members 300 and 302 apart along the central axis ofscrew 306.

[0096] Washer 308 is fitted under the head of screw 306, so that thesurface of washer 308 extends downward from an interior circumference toan exterior circumference. This causes the exterior circumference ofwasher 308 to apply a force toward the surface of member 300. This forcetakes pressure off of member 300 when screw 306 is not fully tightened.Without the force from washer 308, member 300 would tend to pull againstthe holding force applied by jack screw 312—creating strain in member300. This feature can be useful in the manufacturing process ofalignment device 1, before screw 306 is fully tightened so that washer308 is driven to be flat like washer 310.

[0097] D. Optical Reflector Assemblies

[0098]FIG. 9 illustrates five-sided penta-prism 400, which can beemployed to operate as reflector 96. Penta-prism 400 produces an outputbeam perpendicular to a beam entering through input side 402. Inoperation, beam 410 enters penta-prism 400 through side 402 and isreflected by mirrored surface 404 to produce reflected beam 412.Mirrored surface 406 reflects beam 412 to create output beam 8. Inalternate embodiments, reflector 96 is implemented with objects otherthan a penta-prism.

[0099] FIGS. 10A-10C show alternate embodiments for reflector 96 and themounting of reflector 96. FIG. 10A shows penta-prism 420, which can beemployed to operate as reflector 96. Penta-prism 420 generates outputbeam 429 in response to input beam 421. Angle 426 is less than the idealninety degrees between beams 410 and 8 in penta-prism 400. In oneembodiment, angle 426 is 5 arc-seconds less than ninety degrees. Infurther embodiments, angle 426 is designed with a tolerance of plus orminus 5 arc-seconds. The desired value of angle 426 can be achieved inone embodiment by increasing angle 425, decreasing angle 427, orincreasing angle 425 and decreasing angle 427.

[0100] The known decrease in angle 426 is useful for aligningpenta-prism 420, so that output beam 8 is normal to input beam 421. Witha perfectly angled penta-prism, the alignment can be difficult, due tochallenges in mounting reflector 96 on rotation shaft 98 with a zeroroll alignment. A deviation in roll of reflector 96 causes output beam 8to have an incline—increasing the angle between output beam 8 and inputbeam 421. A known deviation in angle 425 or 427 that decreases angle 426makes it acceptable to mount penta-prism 420 with a roll other thanzero. The decrease in angle 426 is offset by deviations in the roll tomove output beam 8 closer to a perpendicular relationship with the inputbeam to reflector 96. In one embodiment, shaft 98 allows reflector 96 tobe mounted within plus or minus 0.1 degree of zero roll alignment.

[0101]FIG. 10B shows a cross-section of shaft 98 in one embodiment formounting an implementation of reflector 96, such as penta-prism 420.This embodiment of shaft 98 makes it easier to mount penta-prism 420with a desired roll. The V-shaped groove at the top of shaft 98eliminates any roll effects that would be introduced by imperfections inthe top surface of shaft 98. The edges of penta-prism 420 are aligned onthe groove surfaces and secured, so that penta-prism 420 has a rollwithin a desired tolerance. In one embodiment, penta-prism 420 issecured to shaft 98 with an epoxy. In one embodiment, shaft 98 allowsreflector 96 to be mounted within plus or minus 0.1 degree of zero rollalignment.

[0102]FIG. 10C shows an embodiment of shaft 98 having decline slope 430on the top surface. When penta-prism 420 is mounted on declined shaft98, the effects of satellite output beams are significantly reduced. Inone implementation, decline angle 432 is offset two degrees fromperpendicular. In an alternate implementation, decline angle 432 has adifferent value. In various embodiments, different penta-prisms can beemployed, such as penta-prism 400 or penta-prism 420. The features ofshaft 98 in FIGS. 10B and 10C are both employed in some embodiments,while only one of the features or none of the features are employed inalternate embodiments.

[0103] In a further embodiment, reflector 96 is partially transmissive,so that a second beam perpendicular to output beam 8 is generated. Inalternate embodiments, different angular relationships to output beam 8can be employed. In one implementation, penta-prism face 404 or 424 ispartially transmissive—allowing the penta-prism's input beam to extendthrough the penta-prism. In further implementations, arefraction-compensated and half-silvered penta-prism is employed. Inorder to allow a beam to pass through rotation cap 6, a window or otheropening can be formed in cap 6.

[0104] E. Manual Rotation Cap

[0105]FIGS. 11A and 11B show a perspective view of rotation cap 6, whichcan be used to manually rotate the position of reflector 96. Rotationcap 6 allows a user's manual rotation force to be applied, while anyextraneous translation forces are ignored. As shown in FIG. 2I, rotationshaft 98 extends through reflector rotation mount 94. Rotation mount 94is coupled to rotation shaft 98, so that the rotation of mount 94 causesshaft 98 to rotate. Mount 94 includes ridge 124. Cap 100 is coupled toridge 124, so that rotation force applied to cap 100 causes rotationmount 94 to rotate shaft 98.

[0106] Rotation cap 6 includes a spring controlled wheel assembly tolimit the translational force applied to cap 100. FIG. 12 shows springcontrolled wheel assembly 500 including wheels 500 and 502. Prongs 504and 506 secure axel 512 passing through wheel 500. Prongs 508 and 510secure axel 514 passing through wheel 502. When a user is not applyingforce to rotation cap 6, axel 512 rests on the bottom surfaces of prongs504 and 506, as shown in FIG. 12. Axel 514 rests on the bottoms ofprongs 508 and 510, as shown in FIG. 12. In one embodiment, prongs 504,506, 508, and 510 are formed using flexible sheet metal or steel.

[0107] When a user presses down on rotation cap 6, axels 512 and 514slide into grooves 520 and 522, respectively, while maintaining contactwith cap 100. When wheels 500 and 502 are in their respective grooves,the top portions of prongs 504 and 506 apply a force on axel 512 thatcauses wheel 500 to maintain contact with cap 100. Similarly, the topportions of prongs 508 and 510 apply a force on axel 514 that causeswheel 502 to maintain contact with cap 100. The friction between thesurface of cap 100 and the surfaces of wheels 500 and 502 preventswheels 500 and 502 from sliding along cap 100, except for rotation abouttheir respective axels 512 and 514. This friction results in cap 100rotating in response to a rotation force applied to rotation cap 6 whilecap 6 is depressed. This rotation of cap 6 adjusts the position ofoutput beam 8 by rotating shaft 98. In one embodiment, the wheelsurfaces are rubber and the surface of cap 100 is plastic.

[0108] For safety purposes, the intensity of output beam 8 can bereduced during a manual rotation. In one implementation, laser outputbeam 8 is reduced to 20% of its normal intensity. In one embodiment,alignment device 1 reduces the intensity of output beam 8 upon detectingthat level sensor 80 has a predetermined deviation from level. Thisoperation is performed by the control subsystem detecting an out oflevel indication and reducing the intensity of the beam from lasersource 116. In various embodiments, different methods can be employed toreduce the intensity of beam 8. In addition to reducing the intensity ofbeam 8, the control subsystem ceases all automated rotation of rotationshaft 98 until a level orientation is re-established. This inhibits thegeneration of laser planes and dithered reference lines.

[0109] F. Producing Vertical References

[0110] In order to produce vertical references, such as lines andplanes, a user rotates alignment device 1 by ninety-degrees. In oneembodiment, the user rotates alignment device 1, so that arms 34 and 36on optics mounting assembly 24 are directed towards the ground. Tofacilitate this orientation, alignment device 1 provides a bubble vialmounted to frame 90, as shown in FIGS. 2H and 2I. In the rotatedposition, bubble vial 90 is on the exposed top surface of alignmentdevice 1 for use by the user in adjusting the position of output beam 8.In the embodiment shown in FIGS. 2A-2I, self-leveling is not provided inthe rotated state. In alternate embodiment, self-leveling is provided inthe rotated state. In the rotated orientation, spring 38 and 40 and thealignment assemblies continue to operate as described above to secureand adjust the position of optics mounting assembly 24 within pivotsocket 22.

[0111] III. Control Subsystem

[0112] A. Architectural Overview

[0113]FIG. 13 is a block diagram of control subsystem 624 in alignmentdevice 1, as well as, alignment motor interface 634, alignment motorinterface 636, optics motor interface 638, level sensor interface 639,local user interface 10, tilt sensor 600, and remote user interface 608.

[0114] Control subsystem 624 controls user interfaces to alignmentdevice 1 and the operation of motors in alignment device 1. Controlsubsystem 624 includes bus 632 coupling controller 628, data storageunit 626, memory 630, and input/output block 644. Controller 628 is acentral processing unit used for executing program code instructions,such as a microprocessor or mircocontroller. In response to program codeinstructions, controller 628 retrieves and processes data and providesdata and control signals. Input/output block 644, data storage unit 626and memory 630 are all coupled to bus 632 to exchange data and controlsignals with controller 628.

[0115] Memory 630 stores, in part, data and instructions for executionby controller 628. If a process is wholly or partially implemented insoftware, memory 630 may store the executable instructions forimplementing the process when alignment device 1 is in operation. Memory630 may include banks of dynamic random access memory, static randomaccess memory, read-only memory and other well known memory components

[0116] Data storage unit 626 provides non-volatile storage for data andinstructions for use by controller 628. In software embodiments of thepresent invention, data storage unit 626 may store instructions executedby controller 628 to perform processes. Data storage unit 626 may,support portable storage mediums, fixed storage mediums or both

[0117] Data storage unit 626 implements fixed storage mediums using amagnetic disk drive or an optical disk drive. Data storage unit 626supports portable storage mediums by providing a portable storage mediumdrive that operates in conjunction with portable non-volatile storagemediums—enabling the input and output of data and code to and fromcontrol subsystem 624. Examples of portable storage mediums includefloppy disks, compact disc read only memory, or an integrated circuitnon-volatile memory adapter (i.e. PC-MCIA adapter). In one embodiment,instructions for enabling control subsystem 624 to execute processes arestored on a portable medium and input to control subsystem 624 via aportable storage medium drive.

[0118] For purposes of simplicity, all components in control subsystem624 are shown as being connected via bus 632. Control subsystem 624,however, may be connected through one or more data transport mechanisms.For example, controller 628 and memory 630 may be connected via a localmicroprocessor bus, and data storage unit 626 and input/output block 644may be connected via one or more input/output (I/O) busses.

[0119] Input/output ports 646, 648, 650, 651, 652, 653, and 654 ininput/output block 644 couple bus 632 to alignment motor interface 634,alignment motor interface 636, optics motor interface 638, level sensorinterface 639, local user interface 10, tilt sensor 600, and remote userinterface 608, respectively. Alignment motor interface 634 is coupled toalignment motor 74. Alignment motor interface 636 is coupled toalignment motor 54. Optics motor interface 638 is coupled to opticsmotor 108. Motor interfaces 634, 636, and 638 provide conversionsbetween the digital data and control signaling of control subsystem 624and the analog signaling of the motors. In one embodiment, optics motor80 has fine cogging and provides sufficient torque to rotate reflector96. Alignment motors 54 and 74 also have fine cogging in one embodiment.

[0120] Level sensor interface 639 is coupled to level sensor 80 toreceive level indicator signals and pass them to input/output port651—converting the analog signals of level sensor 80 into digitalsignals. Tilt sensor 600 is coupled to input/output port 653 to indicatewhen alignment device 1 has been rotated to provide vertical references.Input/output ports 652 and 654 in input/output block 644 couple bus 632to user interfaces 10 and 608. Input/output port 652 is coupled to localuser interface 10. Input/output port 654 is coupled to remote userinterface 608. Local user interface 10 provides a portion of the userinterface for a user of alignment device 1 to control the operation ofdevice 1. In different implementations, local user interface 10 mayinclude an alphanumeric keypad or cursor control device, such as amouse, trackball, stylus, or cursor direction keys. Information providedby the user through local user interface 10 is provided to controller628 through input/output port 652.

[0121] Remote user interface 608 enables a user to communicate withalignment device 1 using remote control 621—allowing the user to provideinstructions. Remote user interface 608 supports the protocol requiredfor facilitating a communications link with remote control 621—providingconversions between the digital signaling of control subsystem 624 andthe signaling of remote control 621. For example, one type of remotecontrol communicates with remote user interface 608 through a radiofrequency connection. Another type of remote control communicates withremote user interface 608 via an infrared signaling connection.

[0122] U.S. Pat. No. 5,680,208 and U.S. Pat. No. 5,903,345 provideexamples of remote controls and remote control interfaces that can beused with alignment device 1. U.S. Pat. No. 5,680,208 and U.S. Pat. No.5,903,345 are hereby incorporated by reference.

[0123] In addition to the above-described components, control subsystem624 may include a display system and a communications controller. Adisplay system enables alignment device 1 to display textual andgraphical information. The display system may include a cathode ray tube(CRT) display or liquid crystal display (LCD). The display system wouldreceive textual and graphical information from controller 628 throughinput/output block 644. Potential communications controllers includenetwork interface cards or integrated circuits for interfacing alignmentdevice 1 to a communications network. Instructions for enabling controlsubsystem 624 to perform processes may be down loaded into memory 630over the communications network.

[0124] Those skilled in the art will recognize that FIG. 13 only showsone embodiment of control subsystem 624 and that numerous variations ofcontrol subsystem 624 fall within the scope of the present invention.The components contained in control subsystem 624 are those typicallyfound in general purpose computer and control systems, and in fact,these components are intended to represent a broad category of suchcomputer components that are well known in the art.

[0125] B. Aligning Horizontal References

[0126]FIG. 14 provides one implementation of a process performed byalignment device 1 to bring output beam 8 into a position parallel totrue level. This process is performed when alignment device 1 ispositioned as shown in FIG. 1. Level sensor interface 639 receives alevel indication from level sensor 80 (step 700). Control subsystem 624determines whether the level indication identifies output beam 8 asparallel to true level (step 702). In one embodiment, this determinationis made using the current values provided by level sensor 80, asdescribed above. If output beam 8 is level, the process in done.Otherwise, control subsystem 624 determines an appropriate leveladjustment to move output beam 8 to the desired position (step 704). Inone implementation, this determination is also made using current valuesfrom level sensor 80. Control subsystem 624 then issues control signalsfor one or more of alignment motors 54 and 74 to reposition opticsmounting assembly 24 (step 706). After the signals are issued, the abovedescribed process is repeated.

[0127] In one embodiment, control subsystem 624 directs the operation ofmotors 54 and 74 one at a time to limit the amount of current drawn byalignment device 1. In one implementation, control subsystem 624achieves small motor movements by giving a motor a first pulse in afirst direction and a larger second pulse in a second direction oppositeto the first direction. This results in the motor moving in the seconddirection. In various embodiments, the second pulse is 4 to 16 timeslarger than the first pulse, resulting in stepped movements in thesecond direction of one seventy-fifth of a full motor shaft rotation.

[0128]FIG. 15 shows one process for alignment device 1 to give outputbeam 8 a desired angular offset from true level. Control subsystem 624first brings output beam 8 to true level as described above withreference to FIG. 14. Once output beam 8 is level (step 702), controlsubsystem 624 determines an offset adjustment to make to optics mountingassembly 24, using motors 54 and 74 (step 712). Control subsystem 624issues control signals for motors 54 and 74 in accordance with thedetermination made in step 712 (step 714). If the offset is correct theprocess is done. Otherwise, the process can be performed again startingwith the leveling operation (step 716).

[0129] In one embodiment, lead screws 46 and 66 have encoders mountedthereon to provide control subsystem 624 with the position of leadscrews 46 and 66. Control subsystem 624 correlates encoder intervals tothe angular movement of output beam 8 to determine the magnitude of leadscrew rotation required to achieve a desired angular offset (step 712).

[0130] In a further embodiment, level sensor 80 facilitates theoperation of a bump sensor. When alignment device 1 is jarred, bubble235 in level sensor 80 undergoes a momentary change, such as a rapidchange in position. Level sensor 80 sends signals identifying thischange to control subsystem 624. In response, control subsystem 624ceases rotation of reflector 96, reduces or eliminates the power ofoutput beam 8, and levels alignment device 1 as disclosed above withreference to FIG. 14.

[0131] C. Aligning Vertical References

[0132]FIG. 16 shows one embodiment of a process for aligning output beam8 when alignment device 1 is rotated ninety degrees from the positionshown in FIG. 1 to produce vertical references. Once alignment device 1is rotated, tilt sensor 600 recognizes the rotation of device 1 andissues a signal. In response to the signal, control subsystem 624 setslead screws 46 and 66 to a predetermined position (step 800).

[0133] In one embodiment, control subsystem 624 directs motors 54 and 74to fully extend each lead screw. Control subsystem 624 detects fullextension from a pair of sensors (not shown) that provide signals uponcoming into contact with lead screws 46 and 66. After both lead screwsare fully extended, control subsystem directs motors 54 and 74 toposition pads 42 and 62 at a predetermined position. For example, leadscrews 42 and 62 are translated to positions that correlate to apredetermined number of motor pulses. In one embodiment, encoders aremounted on screws 42 and 62 to correlate screw translation to motorpulses.

[0134] Once the lead screws are positioned, a user looks at bubble level90 to determine whether optics mounting assembly 24 is leveled—thecentral axis of optics mounting system being parallel to true level(step 802). If bubble level 90 signals a level, the process in done(step 804). Otherwise, the user employs local interface 10 or remotecontrol 621 to direct control subsystem 624 to determine a new leveladjustment (step 806). In one embodiment, the user indicates a number ofdesired lead screw turns, and control subsystem 624 determines therequired signal to make motors 54 and 74 carry out the user definedaction (step 806). Control subsystem 624 then issues the determinedsignals to motors 54 and 74 (step 808). The above-described process inthen repeated starting with step 802. In alternate embodiments, the userprovides different forms of data to specify lead screw movement, such asthe time period a control button is pressed.

[0135]FIG. 17 shows a process for positioning output beam 8 whenalignment device 1 is rotated as described with reference to FIG. 16.This can be useful when a user wants to translate a vertical laser planefrom output beam 8 on an incident surface. As a first step, the levelingprocess described in FIG. 17 is performed.

[0136] Once level is detected, an offset adjustment is determined (step810) for achieving a desired yaw. A user employs local interface 10 orremote control 621 to indicate a magnitude of movement desired from leadscrews 46 and 66. In one embodiment, lead screws 46 and 66 are moved inopposite directions to achieve an output reference translation, whilemaintaining an orthogonal vertical laser plane or line. Controlsubsystem 624 converts the user's input into signals that will drivemotors 54 and 74. Control subsystem 624 then issues these signals formotors 54 and 74 (step 812). If the resulting output reference positionis correct, the process is done (step 814). Otherwise, the process isrepeated starting at step 810. In one embodiment, the user looks atbubble vial 90 and the incident laser beam output to determine if theresulting output beam repositioning is correct. In alternateembodiments, the process shown in FIGS. 16 and 17 are fully automated.

[0137] D. Automated Reference Positioning

[0138] In one implementation of alignment device 1, operators select thelocation of reference lines and points by providing a location inputthrough remote control 621 or local user interface 10—causing opticsmotor 108 to rotate penta-prism 96 into a desired position for areference point or line. In the case of a reference line, motor 108 alsodithers shaft 98 between two positions to create a line on an incidentsurface. Alignment device 1 includes a motor control mechanism thatenables operators to accurately position optics motor 108 when selectingreference line and point locations. In one implementation, motor 108 isa direct drive motor, such as the motors used in compact disc players.

[0139]FIG. 18 shows a process employed by alignment device 1 to positionoptics motor 108. Device 1 controls motor 108 by providing a controlsignal. The pulse width and frequency of the control signal determinethe magnitude of rotation of optics motor 10. Optics motor 108 is firstcalibrated to identify an ideal pulse width for use in motor 108 (step960). Next, device 1 determines the motor control signal necessary forpositioning motor 108 to a desired position (step 962) and provides thesignal to motor 108 (step 964). One implementation steps for performingthe process shown in FIG. 18 us found in U.S. patent application Ser.No. 09/928,244, which is incorporated herein by reference.

[0140] The foregoing detailed description of the invention has beenpresented for purposes of illustration and description. It is notintended to be exhaustive or to limit the invention to the precise formdisclosed. Many modifications and variations are possible in light ofthe above teaching. The described embodiments were chosen in order tobest explain the principles of the invention and its practicalapplication to thereby enable others skilled in the art to best utilizethe invention in various embodiments and with various modifications asare suited to the particular use contemplated. It is intended that thescope of the invention be defined by the claims appended hereto.

We claim:
 1. An apparatus comprising: a pivot socket; an optics mountingassembly extending through said pivot socket; at least one springdirecting said optics mounting assembly through said pivot socket; andat least one alignment assembly in communication with said opticsmounting assembly.
 2. An apparatus according to claim 1, furtherincluding a level sensor mounted to said optics mounting assembly.
 3. Anapparatus according to claim 1, further including a control subsystemadapted to position said optics mounting assembly.